The present invention relates generally to an electrical connector and, more particularly, to a self-locking electrical connector.
Some electrical connectors embody self-locking mechanisms contained in or attached to the connector shell to provide an interlock between the connector halves and to maintain the connector in its mated condition. One such self-locking connector is disclosed in U.S. Pat. No. 3,552,777 to Heinrich. The locking mechanism disclosed in the Heinrich patent is sometimes referred to as being of the "click-stop" type. The interconnection between the mating connector members includes a set of balls uniformly spaced about the periphery which cooperates with recesses or holes in a locking or clicker plate to provide a click-stop effect as the coupling nut is tightened. It is also known to form the holes so as to have a pear-shaped configuration to reduce wear on the locking plate and facilitate rotation of the plate and hence the coupling nut in the clockwise, locking direction. As a result, the anti-vibration locking feature of the click-stop arrangement of the connector is delayed toward final engagement between the mating connector members. However, it is preferred that the locking feature not take effect until final engagement between the connector members. Further, the click-stop arrangement does not provide as positive a lock between the mating connector halves as is desired for some applications in which the connector is subjected to very high shock or vibration. Moreover, the locking mechanism requires a number of additional components, adding to the cost of the connector.
Some electrical connectors provide a more positive self-locking between the connector members. Such a connector is disclosed in U.S. Pat. No. 3,843,853 to Panek et al., assigned to the assignee of the present application. This patent discloses a self-locking mechanism which has been referred to as a "ring lock." In this connector, matching grooves are formed in the outer surface of the plug barrel and the inner surface of the receptacle shell. The grooves are aligned when the plug and receptacle are fully mated. The groove in the plug barrel is deeper than the groove in the receptacle shell. A split ring is mounted in the grooves. In its normal unstressed condition the ring is lodged in both the grooves thereby interlocking the mating plug and receptacle halves of the connector. The locking ring is retained in its locking position by a radially extending pin disposed between the free ends of the split ring. When the pin is removed the split ring is free to be contracted upon application of an axially directed unmating force to the mating connector members.
While the Panek et al. connector locking mechanism is entirely adequate for many applications, the locking arrangement embodies several features which will impose limitations on the use of the connector for certain applications. For example, the locking ring must be mounted on an external diameter and must be allowed to contract radially inwardly. Further, the location of the gap in the split ring must be properly oriented to assure proper engagement of the lock pin therein. Although the ring gap location problem can be solved in a variety of ways, the problem of weight addition to the ring-carrying connector half, and the necessity to carry the ring on an external diameter pose more difficult problems. Furthermore, the ring lock arrangement does not provide a threaded coupling mechanism as is required for some applications to provide a high coupling force to allow interengagement of a large number of mating contacts in the two connector members.
It is the object of the present invention to provide an improved, simple, low cost, self-locking mechanism for an electrical connector which does not engage until the last coupling turn of the coupling nut to the shell thus requiring only a low-engagement force, and provides an effective interlock between the mating connector members which resists loosening of the coupling arrangement even when the connector is subjected to high shock, vibration or temperature working.